What’s up with this Vitamin D thing?
Published 4:34 pm Friday, July 10, 2009
I don’t know if you have noticed like I have, but it seems that I am hearing about Vitamin D a lot more now than ever before.
The knowledge of Vitamin D has been around for a long time. In fact, we have been supplementing Vitamin D in milk since before I was born. Up until recently, however, most of us were under the impression that if you lived in the South, you somehow were immune to Vitamin D deficiency.
Concepts are changing and Vitamin D is getting more press time because our initial impressions have not been borne out.
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Vitamin D occurs naturally in a number of foods, which are available to be included in our diet. Unfortunately, the foods we generally pick to eat are poor sources of this vital nutrient. The richest source I know is cod liver oil. Now when is the last time you had some of that?
Cold water fishes such as salmon, mackerel, tuna and sardines are also reasonably good sources of Vitamin D. They are also rich in protein and antioxidants. Including these fish in your diet is a wise move, but probably not something you are going to do daily.
Milk and boxed cereals have Vitamin D added to them, so that is a source. Eggs, liver and cheese are minor sources, as well. Now looking at your diet, are you getting Vitamin D regularly?
As Southerners, we have always thought that we received enough sunshine to make up for our dietary inadequacies. Sun exposure to your skin does create Vitamin D, just like we have always realized. Think about it though, lately when have you been told to get more sun exposure? The rays of the sun are known to damage skin and thus most prudent individuals limit time under the bright sun.
Staying inside in the air-conditioning also limits this influence. In addition, even though most people don’t realize it, a good sunscreen that prevents sunburn will also prevent production of Vitamin D in your skin. As well, I encourage my patients to use a make-up foundation that contains sunscreen, thus reducing the production of Vitamin D even further.
Vitamin D is necessary in the body because it is essentially required for aiding in the absorption of calcium from our food. Too little Vitamin D intake results in too little calcium absorption, and that affects bone quality.
Deficiency of Vitamin D first came to light as the cause of Rickets, a condition which was once much more common in children. The absence of Vitamin D intake led to broken-down and misshapen bones that disabled kids. Around 1900, it was discovered that cod liver oil could treat this condition.
In adults, Vitamin D deficiency may result in Osteomalacia, or deficient bone. In Osteomalacia, there is plenty of bone present but structurally it is very weak and breaks easily, rather like inferior grade concrete. This is as opposed to Osteoporosis, where the actual amount of bone dwindles. Vitamin D deficiency in adults can result in increased risk of fracture, even with minimal trauma, such as a stumble, for instance.
Vitamin D deficiency can also be associated with deficient muscle strength and occasionally be responsible for muscle and bone pain and aching. Research is not being carried out as to other purported effects of deficiency.
There are some among us that are more at risk of Vitamin D deficiency. Chief among these are our elders. Most older Americans don’t venture into the sun that often anymore. They may also have liver or kidney problems that may impair Vitamin D production. It is also harder for older adults to absorb calcium from the diet and thus they really need extra Vitamin D.
So what do you do?
You should plan to eat cold water fishes twice a week or so. You should consider adding a multivitamin to your diet. You should include skim milk in your diet and other dairy foods, as fat content allows.
Some experts recommend 10-20 minutes of unprotected sun exposure to your arms between 10 a.m. and 3 p.m. twice a week. This advice must be weighed against the known risk of sun exposure in increasing skin cancer frequency. You should also assess your calcium intake.
Most of us just don’t get enough calcium. This is particularly true of women at all times during their life spans from childhood to elder status. For postmenopausal women, the recommended daily intake of calcium is 1,200 mg. Depending on dietary intake, women may need to take one or two calcium supplements to reach that goal. When a calcium supplement is chosen, make sure it includes Vitamin D, usually that will be 400 IU per dose. Those over 75 years of age particularly should aim towards 800 IU per day supplementation.
As physicians, we have started requesting blood levels of Vitamin D more often. We are still getting comfortable with what we consider acceptable levels. We check the active form, 25OH Vitamin D. Levels below 20ng/ml reflect deficiency. We generally like to see levels above 30 and some promote levels above 40.
Patients with Osteoporosis, those with particular patterns of bone loss measured with a DEXA scan, and those with generalized muscle aches or weakness should probably have a Vitamin D level checked.
The good news is that prescription dose supplements of Vitamin D can be taken once weekly or every other week with good effect to resolve the problem. While it is possible to get too much Vitamin D with incorrect supplements or too much cod liver oil, that is very rare. When in doubt, always feel free to ask. Physicians, in general, appreciate patients who are interested in promoting their own health!
The understanding of Vitamin D and its effects is a developing field. The above recommendations may change soon, so stay tuned. For now, look at your diet.
Are you eating the foods you should?
Are you deficient?
What about a supplement?
The price you pay for ignoring Vitamin D may be pain, weakness or broken bones. Think about it; it makes a difference!